Name: Danielle Quill

Date: 01/22/2024

Time (EST/EDT): 01:00 pm

Location: Chesapeake Biological Laboratory, Solomons, MD

Remote Access: email: mees@umd.edu

Committee Chair: Ryan J. Woodland

Committee Members: James Pierson Michael Wilberg Hongsheng Bi

Title: SPATIOTEMPORAL DISTRIBUTION OF CHESAPEAKE BAY MYSIDS IN THE CHOPTANK AND PATUXENT RIVERS, MARYLAND

Abstract: Mysids are a critically understudied, but an ecologically invaluable taxonomic group within Chesapeake Bay. The importance of these small, shrimp-like crustaceans to coastal food webs has been widely documented, but their complex diel movements and seasonal migrations have made thorough field studies of mysids difficult. This study examined patterns of mysid density differences between the Choptank and Patuxent Rivers (including comparisons of sub-genera demographic densities), density changes throughout the sampling season, within-population demographic dynamics, and environmental parameter patterns to determine whether mysids densities are equal in the Choptank and Patuxent Rivers. I hypothesized that mysid densities in the study system will positively correlate with dissolved oxygen and that the Choptank River will display greater mysid densities due to its historically better water quality (particularly dissolved oxygen saturation) than the Patuxent River. Six primary stations in each river were sampled monthly from May to September of 2018. Numerical dominance of the mysid assemblage in both rivers shifted from Neomysis americana to a mixed-species group belonging to the genus Americamysis (Americamysis spp.) between August and September. Total abundance across genera and abundance of Neomysis only were significantly greater in the Choptank River while Americamysis spp. densities were significantly greater in the Patuxent River. The Patuxent River displayed overall lower dissolved oxygen saturation in the summer, which may have influenced changes observed in mysid densities. Understanding the intricacies of population dynamics of important prey such as mysids within nursery areas for ecologically and economically important predators should strengthen ecosystem-based management strategies for those areas.